In many situations it is necessary to euthanize domestic birds such as chickens, ducks, turkeys and geese at the end of their useful life or in the event of a health epidemic. One example where large numbers of birds are required to be euthanized is in regard to laying hens where a whole barn of hens are simultaneously euthanized at the end of their useful laying life, thus allowing the barn to be sanitized and a new batch brought in to start a new cycle.
As the carcases are of no commercial value, it is necessary to dispose of the high volume of carcases which can be done by grinding the carcases into a biodegradable mass which can be simply composted with suitable additives.
It is of course not humanely acceptable to enter the carcases into the grinding system while the birds are still conscious so that some system to kill or at least stun the birds before transportation to the grinding system is necessary.
Up to now, euthanasia has typically been carried out using a gas such as carbon dioxide to kill the birds in advance of removing the carcases from the cages. This is undesirable for many reasons including the risk to workers, the cost of materials, the necessity to have the birds located in a suitable situation where the gas can be concentrated upon them to cause their death. Typically this requires that the birds be removed from their environment into holding cages where the gas can be applied. They often then require further transportation to the disposal location. Another proposal shown in U.S. Pat. No. 7,435,166 (Benson) issued Oct. 14, 2008 uses a foam blanket to smother the birds.
The slaughter of birds for butchering is typically carried out by cutting the neck of the bird to allow bleeding to occur. Many prior art patents show devices for holding and locating the bird to allow the cutting action to occur. For example U.S. Pat. No. 3,490,092 (Harrison) issued Jul. 14, 1967 and U.S. Pat. No. 4,354,296 issued Oct. 19, 1982 both show an arrangement in which birds are carried in leg shackles to location where there is provided a pair of guide bars between which the neck of the bird passes as it is carried to cutting knives which sever the neck. Thus the death is caused by the cutting action and not by the bars which merely hold the neck.
The American Veterinary Medical Association (AVMA) describes euthanasia as “rapid loss of consciousness followed by cardiac or respiratory arrest and the ultimate loss of brain function.” (2000 Report of the AVMA panel on euthanasia. JAVMA 218(5): 669-698.) The AVMA requires that the animal(s) to be euthanized experience minimal distress before being rendered unconscious. There are a number of currently accepted methods for euthanizing poultry include inhalation agents, non-penetrating captive bolt, cervical dislocation, percussive blow, decapitation, maceration, and electrocution. The methods cause death by (1) direct or indirect hypoxia, (2) direct depression of neurons and/or (3) physical disruption of brain activity. Extensive guidelines exist for euthanasia of poultry for processing prior to marketing. However, during emergencies such as a disease outbreak, there are fewer options. The 2000 Report of the AVMA Panel on Euthanasia, devotes only one paragraph on mass euthanasia and states “under unusual conditions, such as disease eradication and natural disasters, euthanasia options may be limited. In these situations, the most appropriate technique that minimizes human and animal health concerns must be used.”